Packing a punch! Scientists now know why babies kick in the womb

Feeling your baby's kick is as emotional as amazing it can get. The first time it happens, it's crazy exciting, and every time after that -- no matter how nerve-wracking it can be sometimes -- it's a reminder that your baby is thriving and ready to meet you. But when a foot lands in your ribs? Not quite pleasant, eh? Well, you can stop wrecking your head reasoning your little one's attempts at mixed martial arts. Scientists have finally figured out why your baby is packing punches!

According to scientists at Trinity College Dublin, in Ireland babies 'move' around because they are trying to develop strong bones and joints. Just as weight-bearing exercises (like running and weight lifting) help build your bones, when your baby puts stress and strain on his tiny limbs, it helps to stimulate and strengthen his muscles and bones.

By analyzing chicken and mouse embryos, the researchers found that determined that movement -- like the non-stop kicking, turning, and stretching babies do inside their mom's bodies – helps stimulate “molecular interactions” that ultimately turn cells and tissues of an embryo into functional bones. They furthered that depending on where the cells are, the movement directs them to either form bone or cartilage.

It must be noted that, if babies don't move often enough, it could be a sign of them having brittle bones or developing abnormal joints. Like adults, babies too need their joints to be covered in “smooth, lubricated” cartilage so they can bend properly.

"Our new findings show that in the absence of embryonic movement, the cells that should form articular cartilage receive incorrect molecular signals, where one type of signal is lost while another inappropriate signal is activated in its place,” said study co-author Paula Murphy. “In short, the cells receive the signal that says 'make bone' when they should receive the signal that says 'make cartilage'.”

So basically, having your baby kick and move around inside you signals more than just them getting comfortable, it means they're actually forming their little bodies. It does sound a little creepy if you think about it too much but it's also really freaking amazing. They develop fingernails in the third week!

Besides bone development kicks also let moms know their babies aren't in distress. Also, it must be noted that moms should start feeling their babies move between 16 and 25 weeks gestational age.